The present invention relates to irrigants for use in apparatus used for scaling of teeth and for lavage of the gingival sulcus and cleaning the sulcular crevice.
The present invention especially relates to irrigants for use in apparatus for high velocity mechanical dental scaling with simultaneous lavage to debride teeth and clear the gingival sulcus.
It is known in the art that plaque and calculus harbor toxic and irritating components implicated in oral disease and that plaque and calculus can be removed from teeth by mechanical scaling, especially at high frequency, and especially at ultrasonic frequencies.
It is also known that the delivery of antimicrobial solutions in the form of lavage has potential therapeutic effect by delivery of medicaments directly to an affected site. Prior art devices comprise thin needle-like delivery tips through which medicaments of various sort may be delivered to the periodontal pocket. There is no vibratory or scaling potential with these devices. Rather any benefit results exclusive from the in-situ delivery of the medicament to the affected pocket.
By contrast, in copending application, U.S. Ser. No. 141,355 assigned to Dentsply International.RTM., incorporated herein by reference, disclosure was made of a fine but mechanically substantial device for delivery of medicaments to an affected site that is simultaneously activated to vibrate and to mechanically debride a periodontal pocket of calculus, bacteria and cellular debris. In the device described, the irrigant issues from the tip of the scaler, and one or more irrigants may be delivered simultaneously. Advantages for such a device are that irrigants may be delivered at the deepest location in a pocket so that when the calculus and plaque are debrided by the action of the scaler, debris may be removed from an affected periodontal pocket, for example, to the mouth. The irrigant is then evacuated by suction to remove debrided material.
In prior art lavage devices the irrigants chosen are those widely available as mouthwashes. These comprise a medicament and a vehicle. Medicaments of implied value include, for example, sanguinarine, chlorhexedine, cetylpyridinium chloride and the like. The vehicle most frequently comprises water, surfactants, a humectant and flavor enhancer typified by glycerin or sorbitol, a viscosity control agent typified by polyoxamer, ethanol as a cosolvent for otherwise immiscible ingredients, flavoring and sweetening agents to disguise otherwise unpalatable taste, a dispersant or surfactant to enhance the miscibility of the ingredients, and coloring agents. The selection of the ingredients is based generally on flavor perception and stabilization of the solution
Examples of commercially available mouthwashes include Listerine, Listermint, Scope, Lavoris, Plax, Chloraseptic, Cepacol The active medicinal ingredients in these mouthwashes include phenol and substituted phenols, thymol, menthol, eucolyptol, methyl salicylate, benzoic acid, eugenol, zinc chloride, cetyl pyridinium chloride and chlorhexedine. The vehicles in all cases include ethanol. The humectants are glycerin and the higher molecular weight stabilizer viscosity control agent, polyoxamer.
Baer, Periodontal Case Reports, Vol 7, No. 1, 1985, has reported that the use of an ultrasonically activated instrument delivering a 3% solution of hydrogen peroxide subgingivally through its tip was a means to "change the environment within a periodontal pocket from anerobic to aerobic" and that the device with "hydrogen peroxide appears to be a safe and potentially adjunctive therapy modality worthy of further clinical trials" Other investigators have suggested the undesirability of applying peroxide in this manner predicated on its cellular toxicity.
In distinction over Baer, the present invention does not contemplate changing the normal oxygen tension within the sulcular tissue. Rather, it provides for removal of contaminating bacteria, toxic debris and antigen products, or the reaction, in situ, of antigens to passivate or inactivate them.
It is known that calculus and cellular debris may harbor antigenic components that trigger a series of reactions within the host that lead to the destruction of soft and hard tissue support of teeth Periodontal diseases are a major worldwide health problem. Collectively they are the major cause of tooth loss over the age of 35 years. The primary etiologic factor is bacterial plaque with dental calculus being a significant modifying influence which complicates treatment. Removal of both plaque and calculus is a prerequisite for improvement and maintenance of periodontal health An objective of the invention is to make materials and methods for the efficacious removal of dental plaque and calculus
It has been found that the combination of high velocity scaling, especially ultrasonic scaling, with local delivery of an irrigant is advantageous
Irrigants are delivered at the deepest location in a pocket so that when the calculus and plaque are debrided by the mechanical action of the scaler, debris is removed, for example, from an affected periodontal pocket to the mouth by continuous flow of the irrigant to the operative site The irrigant is then evacuated by suction to remove debrided material An objective of this treatment is to provide antimicrobial solutions locally so that resident bacteria may be killed and flushed, together with other noxious materials, from the deepest areas of a periodontal pocket.
Because heat is generated by the vibration of stacks and scaling tips, most prior art scaling devices have a conduit that transports tap water to the handpiece and onto the scaling tip for cooling thereof In magnetostrictive devices, for example, the tap water is first used to circulate around the tranducer stack to cool the stack, and is then dispensed onto the scaling tip to cool the tip In piezoelectric devices the cooling water is directed to the scaling tip only.
It has been suggested in copending U.S. Ser. No. 141,355 that irrigants used to deliver medicaments to the site of the treatment can also be used for cooling the stack and/or tip of a scaling instrument.
Also, the delivery of irrigant to the treatment site has the benefit of reducing the local temperature rise. Whether used supragingivally or subgingivally the repetitive vibratory action of the scaler, frequently at ultrasonic speeds, causes localized heating which can produce damage, especially to soft tissues. To avoid these effects, in the prior art, cooling water has been applied to the tip of the scaler by an open stream of cooling tap water delivered near the connection of the tip to the handle with the effect that when used subgingivally the cooling water sometimes could not physically access the action site because of intervening soft tissue. It is an objective of the present invention to provide methods and materials for cooling soft tissue locally so as to avoid traumatic thermal injury.
The irrigants may contain a surfactant which facilitates the removal of calculus and plaque from the tooth by reducing the surface tension of the crevicular fluid normally present so as to permit dislodgment of calculus and plaque. Further, a calcium chelating compound may be present in an irrigant to assist in the dislodgement of calculus, and the solvation, dispersion, and/or emulsification of the endotoxin permitting it being flushed from the tooth and/or soft tissue The irrigants may also contain inhibitors to antigenic components or enzymes and the like which can inactivate their biologic effect on the host. Such compounds are especially valuable in reducing pathogenic effect.
A beneficial effect of the use of surfactants and medicaments is believed to be their ability to disrupt the cell walls of infecting microorganisms to render them non-vital and to reduce their numbers significantly so that recolonization with consequent pathogenic effect is delayed or made impossible. Thus an extended period of time for healing and the growth of non-pathogenic microflora is permitted Plaque, especially subgingival plaque, is frequently consolidated into a sticky conglomerate that is difficult to disperse and remove. It is known industrially that ultrasonication of surfaces expedites dispersion and removal of contaminates, especially and importantly by aqueous solutions when surfactants are present. It is an objective to apply that methodology in dentistry to disperse, solvate and inactivate bacteria and bacterial plaque from periodontal pockets, soft tissue and teeth.
Endotoxins produced by pathogenic bacteria and host cells are believed to induce an inflammatory response which itself is harmful to the integrity of the periodontal attachment of soft tissue to the tooth resulting in pathogenic loss of gingival attachment level and reduction of the underlying bony support. Endotoxins of periodontopathogenic bacteria have demonstrated toxicity against human fibroblasts. These antigenic lipopolysaccaharides are resident in the first few hundred microns of tooth, and are incorporated into the calcified debris which is known as calculus The solubilization of these relatively hydrophobic residues and their removal from contaminated surfaces, for example from plastic tubing, is known to be difficult. It is an objective to provide irrigants containing surfactants and/or chelating agents combined with high velocity scaling and agitation of the irrigant in situ in such a manner that endotoxin is solvated, dispersed and/or emulsified to enhance and facilitate its removal from the sulcus
Another mode of inactiving endotoxin to provide components capable of reacting with the endotoxin to render it non-antigenic. It is an objective to provide irrigants capable of producing such inactivation through the addition, for example, of monoclonal or polyclonal antibodies or reactive peptides or enzyme inhibitors.
Because the treatment may be painful the inclusion of an anesthetic may be desirable.
Irrigating solutions and medicaments may contain a variety of active ingredients that are often unpleasant tasting. To make them more palatable for the consumer it is often the practice to add sweeteners, flavors, and stabilizers that enhance the duration of the preferred taste for an extended period of time. The materials used for this purpose are commonly sorbitol and glycerin and similar hydroscopic polyols. These humectant polyols have, been found undesirable for use in lavage equipment because if they are left to dry in the fine orifices of the scaler or narrow tubing and ports of the supply system they occlude those apertures and make subsequent operation of the equipment difficult or impossible without first flushing with water. Similarly, if the compounds are splashed on hands, operating area or equipment surface, the dried residue is sticky and occludes debris in addition to being aesthetically unpleasant Also, it has been found that for proper flow rate the viscosity of the fluid must be maintained at a level which permits the fluid to flow freely in and from the equipment.
Also, prior art fluids have a tendency to foam which, although advantageous for fighting bacteria, has a tendancy to block the view of the operator from the field of treatment.
It is an object of the invention to provide irrigant formulations containing medicaments, that have a selected viscosity to have a desirable flow rate from the apparatus, do not foam excessively so that the view of the operator is not obstructed, are relatively non-sticky, and are pleasant tasting